Chatter Test

1987 Chevrolet Suburban R20, 7.4 N, 400/M40SECTION Chatter Test

Close shutoff lever at pressure gauge. Slowly depress test stand lever and note whether chatter noise can be heard. Injector should chatter. If there is no chatter, move lever faster until injector chatters. The injector may make "hissing" or "squealing" sound, instead of chatter, this is also acceptable. Replace injectors that do not chatter.

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.